mm: remove gfp_mask from add_to_swap

mm: remove gfp_mask from add_to_swap

Remove gfp_mask argument from add_to_swap(): it's misleading because its
only caller, shrink_page_list(), is not atomic at that point; and in due
course (implementing discard) we'll sometimes want to allocate some memory
with GFP_NOIO (as is used in swap_writepage) when allocating swap.

No change to the gfp_mask passed down to add_to_swap_cache(): still use
__GFP_HIGH without __GFP_WAIT (with nomemalloc and nowarn as before):
though it's not obvious if that's the best combination to ask for here.

Signed-off-by: Hugh Dickins <[email protected]>
Cc: Lee Schermerhorn <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Robin Holt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>